1. Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského Nám. 2, 162 00 Prague 6, Czech Republic
2. First Faculty of Medicine, Charles University, Salmovská 1, 120 00 Prague 2, Czech Republic
3. Institute of Physiology, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague 4, Czech Republic